Wrist mechanism for artificial arms



Aug. 5, 1952 K. c. vEsPER WRIST MECHANISM FORARTIFICIAL ARMs 2 sx-IEETs-SHEET 1 Filed Dec. 5, 1947 Aug. 5, 1952 K. c. vEsPER WRIST MFcHANIsM FoR ARTIFICIAL ARMs Filed neo. 5, 1947 2 SHEETS-SHEET 2 /foo vvE/vrop: KARL C l/Espf@ M .w m rm m M so. Il m H Patented Aug. 5, 1952 lUNITED STATES PATENT OFFICEA WRIST MECHANISM FOR ARTIFICIAL ARMS Karl C. Vesper, Santa Monica, Calif., assignor to A. J. Hosmer Corporation, Santa Monica, Calif., a corporation of California Application December 5, 1947, serial No. 789,801

5 Claims. 1

My invention relates toprosthetic devices and particularly to an articial arm for use by abovethe-wrist amputees and having a forearm to which a hand is connected. Specifically, the invention pertains to'an improved wrist structure for detachably connecting the hand to the forearm and to center-controlled means for actuating the grasping hook or finger of the prosthetic hand.

It is desirable, in artificial arms of the class referred to, that different types of grasping hooks be used at the will of the amputee to perform various functions. For example, when the arm is not used to perform work, an artificial hand closely resembling a vhuman hand in appearance, but having stationary fingers, may be employed. However, when the arm is to be used to perform work, such as lifting objects, it is necessary that either a hand having movable fingers or jaws or a prosthetic device having one hook or a pair of movable hooks be employed so that the objects can be grasped between the jaws or hooks and lifted by the arm when the latter is flexed at the elbow. It is therefore desirable that the wrist portion of the arm be constructed in a manner such that it is capable of connecting various types of hands to the end of the forearm. To provide for maximum utility of the hand and to ad'apt it to perform certain operations, it is necessary that the hand be connected in such manner that it can be turned with respect to the forearm to obtain full pronate, supination action. Moreover, it is highly desirable that the hand be capable of closing and opening' in order to adapt it to grasp and release objects.

, It is a primary object of my invention to provide a prosthetic arm which meets all the prerequisites enumerated above so as to make the arm l,more universal in use; It is an important object in this respect to provide an artiiicial arm in which is embodied an improved wrist joint capable of releasably connecting or locking a hand member to the end of the forearm such that the hand member is positively retained in place to resist considerable force which might tend to disconnect the same. In its preferred form, the hand retaining means includes a releasable latch which is adapted to engage in a peripheral groove in the shank of the hand member so as to effectively retain the hand member connected to the forearm while permitting relative rotation or angular adjustment between the forearm and hand member in both pronate and supinate directions, and this is another object of the invention.

.l .It is a further object of the invention to provide a wrist device embodying means for retaining the hand member in different positions of angular adjustment. In accordanceV with a preferred construction, this meansV consists :of one ory more brake shoes which are movable radially within the wrist device and which are adapted to engage the periphery of the inserted shank ofthe hand member to frictionally resist turning thereof.

Another object of the invention is to provide a wrist device which includes two mainr ele ments, one element being rigidly secured to the end of the forearm and the other element being rotatable on the rigid element, the rotary element being provided with cam means adapted, upon rotation of the element in one direction, to apply the brake shoes to the shank of the hand mem-v ber and operative, when rotated inthe opposite direction, to permit release of the brake to effect free rotation of the hand member.

It is a further object to provide a wrist device, of the type referred to, in which the latch is care ried by and pivoted on the rotary element and to provide means whereby the latch is pivoted to locking position upon rotation of the rotary element toward brake-applying position andipivoted to unlocking position upon rotation of the rotary element to and beyond brake releasing position so that the brake is released prior tok the unlocking of the hand member. By this improved construction, the operations of locking and unlocking the hand member and applying and releasing the brakes are accomplished by the simple act of rotating the rotary element in either direction. This is a very desirable feature since it permits convenient and .quick locking and unlocking of a hand member without 'requiring tightening and loosening Vof screws or other detachable fastening means commonly em,- ployed for such purposes. Moreover, by this im? proved structure the hand .members can vbe readily interchanged and may be angularly ad'- justed without releasing the retaining means so that the adjustment can beI made with'the hand directed downwardly without causing disconnection thereof.

Another object is to provide a wrist 'device in which the several parts are heldin assembled relationship by means of a single element, namely, the latch which retains the hand member connected to the Wrist, the latch being carried by the rotary element of the device and normally engageable with the fixed element of I the device but adapted to be movedto disengage the fixed element so as to permit separation of the two elements. Thus the wrist devicevmay 3 be assembled and disassembled by merely actuating the latch and it is apparent that this makes for simplicity of operation and greater economy of manufacture since it eliminates screws, rivets and other fastening means which would be inserted during the assembly of the parts.

In additionito the-features outlined above, the present invention has for another object the provision of hydraulic means incorporated in the wrist device for voluntarily actuating one or both of the fingers or jaws of the artificial hand. In its preferred construction, the hydraulicmeans consists of a cylinder within the wristL structure and a piston slidable in the cylinder and having an outer extension or stem operatively connected to at least one of the movable jaws, said stem being adapted when fluid pressure is exerted against the piston, to relatively shift the jaws toward and away from each other to permit the jaws 113.0 embrace Yanobject to be grasped therebetween ,and to cause opening of the jaws to release the object at the will of the amputee.

'Various types of artificial Yhands Vhave* been employejdin the past and it is the usual practice to' operatev the movablev fingers or hooks thereof by' means of cords or cables arrangedexternally of the arm and connected to a shoulder harness so .as to be pulled in response to a shrug ofthe shoulder. Such exposed cables are apt to catch gainst the clothing of the-wearer and are otherwise inefficient' for other reasons. It is therefore an important object of the present invention to provide Ua Combination wrist and hand structure 'in which the fingers or hooks are operated by a so-called center control wherein lthe remotely controlled means for operating they hooks is 'movable within the wrist and, in the case of an above-the-wrist.amputees through the' articial forearm. By this construction and-V arrangement of parts, the hook or hooks can be operated either by a cable or by hydraulic means movable entirely Vwithin and centrally of the wrist and forearm, ,and one or a plurality V0f the fingers or hooks can be actuated by the single actuating means.

Further objects ofV my invention will be apparent from the Afollowing specification andV the drawings, whih are intended for'the purpose of illustration only. and. in which:

' Fig; lis a side View of an artificial armemloQdyinef-the features 0f' the invention, the wrist device'being shown in section to disclose the interuel structure thereof.; t

, 1Fig., 2 is an l enlarged longitudinal section, taken 0n ,1ine2f2 of Fie 1';

` r3 is an enlarged cross-sectionalview taken on line 3-3 'of Eig, 1 vshowing the brake lmeans released: 'i V Fig. 4 is a View similar to Fig. 3 but illustrating the brake means applied;

'Fig'.g is alongitudinal sectional view through a vwrist device of modied Construction, in which apair of fingers or hooks is actuated .Simultaneously;'and

, Fig is .a side view of an alternative structure in' .whih themovable linger or hook is'moved to operative positioniby means of a control cable.

{Referringjfirst to'Figs. l to 4 ofthe drawings, my `improved wriststructure isrshown as applied tousein a prosthetic arm `consisting of a tubular forearm 5 of conventional shape and a `hand 6 detachably connected to the forearm by means of thejpresent'wrist device 1. ',Ihe forearm 5 may Tbe provided vwith h'ingestraps 8 for use in connecting it to an'upper arm- (not shown) when 4 the artificial arm is used by above-the-elbow amputees, but in cases where the arm is used by above-the-wrist amputees the upper hinge portion is dispensed with and the forearm made in the form of a socket for receiving the lower end of the forearm stump to which it may be attached by any known means. The forearm 5 may be constructed from moldable' plastic or other material and held in its lower end is an insert or socket member I0.

'The socket member I0, which constitutes one of the main elements of the improved wrist dev ice 1, is annular in'outline and has a rearward portion II `adapted to fit into the lower end of the forearm 5. Preferably, the end II of the socket-member lIll is. molded into the end of the forearm vto provide a permanent connection therebetween. The socket member I0 has annular wall l2 disposed midway between its ends and projecting*forwardlyv from -this wall is a sleeve'portion I3 having a bore or'socketf I4. An annular space or recess I5 isA provided between the Vouter circular wall I3 and the periphery of the sleeve portion I3.

Forwardly of the wallgl Vthe sleeve 'portion I3 is providedwith a Apair-of diametricallyopp with obtuse points 2l. Leaf-sprmgs 'have-their endsv engaged under'theprojections 2 0 Aofiithe opposite shoes I9 Vand ltend to urge the shoes radially outward, the springs being capable of flexing or bowing, however, so that the shoes can be forced inwardly by means to be'presently described. The sleeve portion -I3 is also provided with a slit 23 (Figs. 1', 3 and 4) vthrough which t a latch, to be later describedfis adaptedtomove.

A pair of semi-circular grooves or recesses 2l is provided in the inner-surface of the -vvall' I6 of the'socket member I-IJ at diametrically opposite locations, the recesses being disposed adjacent the pointed ends 2| vof the brake'shoes I9. Inthe recesses-'21 are Vpivotallymounted the rounded ends v28 of a pair of arcuate brake levers :3 0 which extend alongside 'the inner surface ofthe Wall I6, each extending through substantially ninety degrees, the free ends-ofthe levers' being beveled.

The rotatable element of the wrist vdevice lcomprises gan annular cap 3| vwhich has a circula-r wallf32, an inner annular flange 33 and-anfouter annular wall 34. The inside 'diameters Vof YVthe flange 33 and wall stare such thatthe cap member 3I'may be slidaxially onto the sleeve-portion I3 to adapt it to rotate thereon. The cap vmem- I ber 3f is provided on its rearward'face with' a vpair of diametrically-op-posite cams 35 of vsemicrescent shape. 'I-'he outer curved surfacesof the-cams 35 are concentric Awitlfrthe axis-"of the cap mem-ber SI to adapt themjto fit -withnthe annular recess I5 and to rotate against the-wall Itofthe socket member III'.Y` When the cap'mem` ber 3l is rotated in eounterclockwisey direction, as viewed yin Figs. 3 and 4, thethin leading ends ofthe cams 35i will engage lthe beveled ends of the'brake lever 30 'and'continued-rota'tion of the cap member will cause -the cams to pivot the levers inwardly as shown in Fig. 4. Through the engagement of the levers y'30 -Withtheouter pointed ends of the brake shoes I9, the latter are slid inwardly.

Disposed against the outer surface of the inner annular flange 33 of the cap 3 I, and pivoted on a ypin 31 extending between the flange and the outer annular wall 34, is a latch member 38. Thelatch member 38 has a curved end portion 39 and-'a curved finger-piece 4B projecting later.- ally from the end of the curved portion and positioned in a rectangular aperture 4I `in the circular wall 32 of the cap member 3 I The latch member 38 is normally pivoted in counterclockwise direction,as viewed in Figs. 3 and 4 under the action ofaspring 42 coiled around the pin 31 and having one-of its ends bearing against `the circular wall i2-'of the cap member' and its other end'hooked across the edge of thelatch vmember. Pivotal movement of the latch member 34 toward the 'axis of the cap member 3I is limited by the engagement of a tail piece 43 of the latch member against the inner surface of the circular wall 32.

The hand member I includes a body portion 45 having a claw-like finger or hook element 46 projecting from one end thereof, the interior surface of the element being preferably lined with rubber or other resilient material 4l'. At its opposite end, the member 6 is provided with a 'tubular extension or shank portion 48 having an outside diameter slightly smaller than the bore I4 of the sleeve portion I3 vof the socket member I to adaptr the shank portion to be inserted therein and the hand member to rotate with respect to the forearm 5. The shank portion 48 is provided with a peripheral groove 50 in which the curved end portion 39 of the latchmember 38 is adapted to engage to rleasably retain the hand member in place. g

To apply a hand member 6- to the end of the forearm 5, the cap member V3| is rotated in clockwise direction and eventually the latch member 38 will engage an end 23 of the slit 23 of the sleeve portion I3 and thus be cammed outwardly against the action of the spring 42 to the position indicated by dot-and-dash lines in'F'ig. 3. At thesame time the-cams 34 will be moved from engagement with the brake levers 36 so that the brake shoes rI9 are free to move radially outward under the influence of the leaf lsprings 22. The interior of the sleeve portion I3 is thus free o'f'obstructions and the shank portion 43v of the Ahand member 5 may be inserted thereinto as shown in Figs. 1 and 2, with the body portion 45 abutting the outer-surface of the cap member 3|. `rI'heA insertion of the shank portion 48 bythe nor- 'mal or sound hand o f the vamputee is greatly facilitated if the forearm 5 is held with the wrist device -l uppermost.

Q After the hand member 6 has been applied in the above manner, the Ycap member 3I is rotated Ain reverse or counterclockwise direction to a slight extent to cause the latch member 38 to move awayvfrom the end 23' of the slit 23. At this juncture, the spring 42 acts to swing the latch thus serves to retainv theshank portion within the wrist device I while permitting rotation of the l hand member 6.

`It is desirable that the hand member beheld in different positions of angular adjustment with respect to the forearm and this is-particularly 'true when so-called work hands areemployed.

With V'the 'artificial arm. lowered, .the amputee rother part of the torso of the wearer.

turnsthe hand member 6 to any desired position, and' thereafter rotates the cap member 3I to a further extent in counterclockwise direction. During this additional rotation, the latchmember 38 remains engaged in the peripheralgroove 59 and the cams 35 moveunder the brake levers 30 to pivot the latter inwardly as shown in Fig. 4 so that the brake shoes I9 are moved radially inward to cause their friction pads IB to engage the periphery of the shank portion 48 to prevent rotation of the hand member 6 withrespect to the forearm 5. It is thus seen that the hand member 6 is effectively retained withinthe wrist device 'i by the latch member 38 and held against rotation by the brake pads I8. To remove the hand member so that other types of hands may be applied to the forearm, the operation is reversed, that is, the cap member 3I is rotated in clockwise direction to first release the brakes and thereafter disengage the latch member 38 from the peripheral groove 50 of the shank portion 48 to ypermit withdrawal of the hand member.

Work hands of the type shown in Fig. 1 are commonly provided with a finger or hook 55 which is movable toward and away from the fixed hook 45 to enable the amputee to grasp objects between the two hooks and to release the same therefrom. i The'upper end of the finger 55 is preferably located within a slot 56 in the body portion 45 and is pivoted on a transverse pinv 56 extending across the slot.Y The finger 55 may have a rubber pad 5l` on its inner surface. The finger or hook 55 is normally pivoted to closed position against the fixed jaw 46 by means of a coil spring 58.

It is desirable that the hook 55 be pivotally moved to openk position by manually controlled means, and the present invention contemplates the provision of fluidv actuated means for effecting such movement. Referring to Figs. 1 and 2, the movable hook 55 is provided with anvoffset lug 69 which is positioned in alignment with the axis of the shank portion 48. Screwed into the upper end of the socket member I0 is a disc 6I which carries a fluid cylinder 62, thecylinder being closed at its upper end by a sealed plug 63. The cylinder t2v extends down into. the shank portion ll'and has a sealed lower end. Adapted to slide vertically in the` cylinder 62 is a piston 55 provided with an axial stem t6, the lower end of which engages the onset lug 60 of the pivoted hook 55. Hydraulic fluid may be introduced into the upper end of the cylinder B2 and into the hollow piston 65 by means of a hydraulic line 61 passing through holes in the disc 6I and plug 63. The upper endof the hydraulic line 67 may be connected to any suitable pressure creating means which may be operated in response to movement of an arm, shoulder or When hydraulic fluid is forced into the cylinder 62, the piston 65 is moved downwardly to swing the pivoted hook 55 away from the xedhook 46 -and when the' pressure of the iiuid is relieved,

the spring 58 returns the pivoted hook to closed position. y A

Referring now to Fig. 5, the vpresent'invention contemplates the provision of a combination wrist and hand structure Iin which the lingers or hooks 6I and 62 are adapted to be pivoted toward and away from each other to grasp and release various objects. This alternative struc- -tureisadapted to be appliedto the end of a forearm' member 63 and, as inthe -embodiment previouslyY described.. the Ystructure includes. a

socket fmember.; 6,5, i :an annular cap member 65 rotatable .about vthe :axis of fthe;V socket. member, braking v.means 166:.and a latch member. V16'?. Screwed-.into `:the..upper threadedend. of the socketmemberf .isa cylinder memberfwhich has .a vlower axial.A extension 1) .disposed v,within the socket member. and `,defining therewith an annular .opening f1.l, .andpannpper axial exten sioni-1.2. The cylinder.member.e69ehas an .axial bore 13...extendingthroughout thegreater part of :its length .-.and in the upper end of the...ex tension =.'|2 is..a counterbore 4providing .a cylinder 1A-,f the uppenend 4of .the-.cylinder .being .closed by .a .plug 15 @screwed thereinto..vand having a smallwvent. orice :10. Slidable :within .the ey-4 linder TML-is a piston 'i1-.which has anintegralrod I8 adaptedto slide .in the bore u'7.3 andcarr-ying .a vpin -7|9.adjacent.its lower. end. Hydraulio..-uid is adapted to be introdueed.- into the Ylowerend of the cylinder 214 through. a port .S 'in .which the.y end of a. hydraulic linel is held.

.A hand member indicated generally at 8 3,.,has a tubular portion-84 adapted to rbe-ireceived in theannular openinglll and to be retainedthereinby-means of Ithe latchlmemberis. The hand member 83-also-hasa discportion 85 which abuts the loutersurface of the `cap member.` S :when the handnember is attached to the Ywrist device. The hand Imember 83 has afpaireofvspacedears or flanges between which arepivotally mounted, Aon transverse pins 88-and.-.89, the pair of hook members `5| and ;B2. Springs .92 .and #93, 4ceneri around lthe respective pins .sa .and ses, each-have one of theirends' resting againstthe disc portion 85 and their other ends engaging the hoolrmemberslll and .-62. The .springsil and 93 function to .normally pivot the hook vmembers away from each other .to the openpo.- sition shown by full lines in-Fig..5 so as toadapt them to receiveean article tobe .grasped there? between.

The hooktmembers .6|andf2 fmayzbe of any -desiredshape and lat their upper .ends..they,are provided with integral, lslotted .lugs l 9.4and 2.85,

respectively, which `are -positioned .at l.opposite :Y

sides ofthe lower end ofthe piston rod '18 tore- -ceive the pin'19 which operativelyconnects the hook Vmembersto the piston rod.

v Assuming that the hook members vEil vand-62 are -held-in the Aposition shown in full linesby the springs l92 and :93, the hoohmembers-may lbe drawn ltogether vto .clamp an object .therebetween by merely swinging lthem toward .each other.v To eiectV such Vpivotal movementof the rhookmernbersl| and 62, lhydraulic fluid is forced into the lower end ofy the cylinder -14 4tocause Athe pistonvl'l and its rod I8 to be .slid upwardly. 'The `hydraulic line 8| may be .connected tof a compressible bulb or other-manually--operable ydevise which acts tolforce fluid through the .line land into Ythe cylinder.

Y `As the 4pistonnrod :1B eis drawn iupwardly, it acts through its pin .19 -and the lugs f94vand95fto .pivot -the hookfmembers fluid pressure lis -reduced inthe lower vend ofathe cylinder -|4, the --springsSZ and 93--act1-to 4return the 'hook members l'6| and B2 tonopen position'and move the piston .71 lto v'lowermost po- Y sition.

Referr-i-ng now to Fig. l6, `the presentinvention contemplates a combined Vwrist and hand-structure Y |00 of -lf-urther modied construction. As

is fadaptedzfor,attachment-to the end -of-,. an iartif ficial forearm |0|. The alternative structure shownJnf-Fig. ',6-Ais smilarto that-disclosed-in Figs. f1 v.to 4. except that mechanical voperating means isfsuhstituted lfor the .hydraulic means thereof. -Ehe ihandymember |02 shownin Fig. 6 ine1udes.;a;nxed ebook-f member |04 ande `hoek member-l-llgpivotedonapin |-06to adapt it t0 pivot .toward l1arid-.awwfrQm the Xed -heek member. .Aspirine v10.1 having. its. ends engagingthehandmember Inland the hook member |05, .grespectively,normally functions topivot the 11.0.01; member A05 to..:Qp.en-.p0si.ti0n.Shewn- .The hookemember ftghasA va lug |03 `to'whieh is attachedrenefendfoffa :eerder-sable 1.09,. .the .Cable passing. np dlr-through .the Center 0f; the Vwrist.device. .ndlf0reermendi-beine suitably een- `meeted.1.1.0 .a shoulder 1h ..-ness .0r any ether eepliance, capable@ being-.operated bythe efe.- putee.. Whenzthe v:eend :|09 viS .pulled upwardly thehook-member |05 is pivoted to closed-posi.- tion to clamp an-object between this member and the -fixed -hook member |04. When the cord -|0 9isreleased, .the spring |01 returns thehook member 10e-t0. .enen lposition.

While-1 have .-hereinshown and described my 'improvedarticial arm embodied in several preferred forms of construction, by way of exfvaprirne, itywill ber :apparent that further ,modifications might be made therein without departing fromwthe spirit of :the invention. Conseqdently, I do `not wish to be limited in this refspect, but desire to be afforded the full .scope` of tbeappended .elemev .I .elem eermy. invention 1. -Ina prosthetic device of the class vdescribed comprising a cooperating artificial limb proximal member and anarticial .limb terminal member, one of vsaid members rhaving an 'annular `groove :extending transverselyof and lsubstantially ,coax with the jpronation-supination axis, a latch carrie bythe other -of said members land dis#- fpesed in @eid :groove connecting Seid members .againstaziial displacement Dwith complete :freedom -for A relative rotar-y f adjustment about said pronationnsupinatonaxis, .said latch being reltraotible fromy ysaid groove for completely ldis-- .CQIiIleCting said members to permit separation thereof,- frictionbrake means carried by .said Qtherr of. s aid members Vfor retarding relative rotary mog/ ement ,of lsaid .members about the pro.-

, nationesupination Jaxis with any desired degiee of resistance from its release `position aordng complete freedom of relative rotary movement toits'iully applied position for effectively lock.- ing saidmembersfrom said relative rotary moyement, means operable at an in nite numberfof ROSiiOnS'Qf VYrelatye rotary :movement ofsaid nsubstantially parallel. to said pronation-ysupina tionY axis, and 'pressure responsive means carried by ys aid .proximal member andfresponsive to exf- V.tension of Ysaid extensible means for actuating said terminal member.-

2. In a prosthetic device of the classdesribed '.QQmlriSng `a cooperating artiflcial limb proximal member and an .erteiel .limb -termnel member, one 0f lsaid .members lhaving an annuler A Y sleeve extendingtransverseiy v`or and substanin the Yprevious embodiments, the structure |00 117.5 z-.tieilly-.coaxia1 with the pronationrsupinatonvaxis,

a latch carried by the other of said members and disposed in said groove connecting said members against axial displacement with complete freedom for relative rotary adjustment about said pronation-supination axis, said latch being retractible from said groove'for completely disconnecting said members to permit separation thereof, friction brake means carried by said other of said members for retarding relative rotary movement of said members about the pronation-supination axis With any desired degree of resistance from its release position affording complete freedom of relative rotary movement to its fully applied position for effectively locking said members from said relative rotary movement, means operable at an infinite number of positions of relative rotary movement of said members for controlling the effectiveness of said brake means to any desired degree through any increment of said relative rotary movement, hydraulically operable extensible means carried by said proximal member and substantially encompassed by said annular groove for extension toward said terminal member substantially parallel to the pronation-supination axis, displaceable abutment means carried by said terminal member and responsive to extension of said extensible means for actuating said terminal member.

3. In a prosthetic device of the class described comprising a cooperating artificial limb proximal member and an articia1 limb terminal member,

one of said members having an annular groove extending transversely of and substantially coaxial With the pronation-supination axis, a latch carried by the other of said members and dis-s posed in said groove connecting said members against axial displacement with complete freedom for relative rotary adjustment about said pronation-supination axis, said latch being retractible from said groove for completely discon- L- necting said members to permit separation thereof, friction brake means carried by said other of said members for retarding relative rotary movement of said members about the pronation-supination axis with any desired degree of resistance from its release position affording complete freedom of relative rotary movement to its fully applied position for eiectively locking said members from said relative rotary movement, rotary means for controlling said brake means and said latch, means responsive to rotary movement of said rotary means through one portion of its rotary movement for controlling said latch from and between its disengaged position and its Vposition of engagement in said groove, means responsive to rotary movement of said rotary means beyond said one portion of its rotary movement for controlling the action of said brake means between its release position and its fully applied position at any of an infinite number of positions of relative rotary adjustment of said members, hydraulically operable extensible means carried by said proximal member and substantially encompassed by said annular groove for extension substantially parallel to said pronation-supination axis, and abutment means carried by said terminal member and responsive to extension of said extensible means for actuating said terminal member.

4. In a prosthetic device of the class described comprising a cooperating artificial limb proximal member and an artificial limb terminal member, one of said members having an annular groove extending transversely of and substantially coaxial With the pronation-supination axis, a latch carried by the 'other' vofsa'id members and disposed in said groove connecting said members against axial displacement with complete "freedom for relative rotary adjustment about said pronation-supination axis, said latch being retractible from said groove for completelyrdisconinecting said members to permit separation thereof, .friction brake means carried by said other 'of said members for retarding relativerotary movement of Said members about the Dronati'on-supination axisv with any desired' degree of resistance from its release position affording complete freedom of relative rotary movement to its fully applied position for eiectively locking said members from said relative rotary movement, rotary means for controlling said brake means and said latch, means responsive to rotary movement of said rotary means through one portion of its rotary movement for controlling said latch from and between the disengaged position and its position of engagement in said groove, and means responsive to rotary movement of said rotary means beyond said one portion of its r0- tary movement for controlling the action of said brake means between its release position and its fully applied position at any of an innite number of positions of relative rotary adjustment of said members.

5. In a prosthetic device of the class described comprising a cooperating artificial limb proximal member and an artificial limb terminal member, one of said members having an annular groove extending transversely of `and substantially coaxial with the pronation-supination axis, a latch carried by the other of said members and disposed in said groove connecting said members against axial displacement with complete freedom for relative rotary adjustment about said pronation-spination axis, said latch being retractible from said groove for completely disconnecting said members to permit separation thereof, friction brake means carried by said other of said members for retarding relative rotary movement of said members about the pron'ation-supination axis with any desired degree of resistance from its release position affording complete freedom of relative rotary movement to its fully applied position for effectively locking said members from said relative rotary movement, means tending to retract said friction brake means to its release position, means urging said latch into said groove, rotary means operable successivelyv in one direction of rotary movement for releasing said brake means and then for retracting said latch from said groove, said rotary means being operable successively in the opposite direction of rotary movement thereof for releasing said latch for lodgment thereof in said groove under the influence of said means for urging said latch into said groove and then upon further rotation for applying said brake means with progressively increasing effectiveness as the rotary movement continues, hydraulically operable extensible means carried by said proximal member and substantially encompassed by said annular groove for extension toward said terminal member substantially parallel to the pron-ationsupination axis, and abutment means carried by said terminal member and responsive to extension of said extensible means for actuating said terminal member.

. KARL C. VESPER.

(References on following page) 

